Google DNS --- Figuring out which DNS Cluster you are using

[nanog at shat.net (Shaun)]

On Wed, 23 Aug 2017 20:09:49 +0000
Erik Sundberg <ESundberg at nitelusa.com> wrote:

> Which Google DNS Server Cluster am I using. I am testing this from Chicago, IL
> 
> # dig o-o.myaddr.l.google.com -t txt +short @8.8.8.8
> "173.194.94.135"                     <<<<<<DNS Server IP, reference the list above to get the cluster, Council Bluffs, IA
> "edns0-client-subnet 207.xxx.xxx.0/24"                                  <<<< Your Source IP Block

Worth noting, this record has TTL 60 and caching can cause unexpected
responses; you may have to try a few times to get the correct data. My
first attempt gave me an unrecognized "edns0-client-subnet" and a Google
IP from Finland when I was querying from Atlanta.

-s